Aenglum: A gritty and dark place?

I always try to keep things fun and so on, but Aenglum is a dark and gritty place in the end. When you make rules you want them to be functional and easy, and foremost make sense. How do you add the element of "dark and gritty" to such a formula? Is it mostly by having the feelings you want portrayed in the actual descriptions of each and every stat, ability and skill? Is it in the presentations of adventures, people and places? A combination of these two? Is it a consistency in what you portray to the public?

What if it is how you make the brightest light in the world shine? If this light is dim and dark, the world must surely be a piss-hole to live in right?